Edhellond was situated upon a jagged islet at the mouth of the River Morthond, making access impossible for all except the invited visitors of the Elves. One entered the city through sea-caves which housed a small Elven fleet in safety.
Edhellond was uniquely the only non-Mannish settlement in southern Gondor. Originally founded as "Lond Duilin" at the mouth of the Morthond-Ringló during the late First Age by Falathrim fleeing from the power of Morgoth in Beleriand, Edhellond came to be one of the chief havens for Elves departing Middle-earth into the West, until its last ship departed in T.A. 1981. From the time of its founding, Edhellond had served as a dwelling place for some of the mightiest of the Eldar in Middle-earth and though the Elves were for the most part estranged from mortal Men during the Third Age, nevertheless the aura and memory of their presence had a profound effect on the fortunes of southern Gondor.
In the year 474 of the First Age, Morgoth's had overwhelmed and destroyed the havens of the Falathrim in Beleriand, forcing Cirdan the Shipwright's folk to leave southward. One Company, led by Cirdan's son Cirdur. sailed farther than the rest, and at last entered the sheltered waters of Lond Cobas, opposite the mouth of its rivers. Because of the enduring threat of Morgotb in the north, Cirdur sought out a defensible site where he might build a fortified refuge for his people. Cirdur chose to found his refuge upon a rocky islet near to the western bank of the river mouth, and he named it "Lond Duilin" (S. "Haven of the Rivers").
During the beginning years of the Second Age, after the threat of Morgoth had been vanquished by the Valar in the War of Wrath, Cirdur's haven was enlarged by many Sindar corning from the wreck of Beleriand. These were the refugees from Doriath and were led by Amdir and his son Amroth. Because of their enmity with the sons of Feanor, Amdir and his people had refused to acknowledge the high kingship of Gil-galad over the Elves of the Westlands and had wandered south in search of a dwelling apart. Because of the ancient friendship between the Falathrim and Sindar of Doriath, Cirdur welcomed Amdir's folk, joining them to his own.
With the aid of the Falathrim, the Sindar built houses for themselves on the river bank opposite the fortification of Lond Duilin, and eventually constructed a larger and more permanent haven, which they named Edhellond. Since the threat of Morgoth was no more, the greater part of the ship-building Falathrim and the woodland Sindar chose to live side-by-side on the western bank, maintaining Lond Duilin as a secondary refuge only in times of need: thereafter, both settlements were referred to collectively as Edhellond. Despite Amdir's distrust of Gil-galad, there was much contact between Edhellond and the Grey Havens of Lindon. Along with its sister haven to the north, Edhellond came to serve as one of the principal points of embarkation for Elves desiring to leave Middle-earth for the Undying Lands, and Cirdur was its Chief shipwright.
In S.A. 1780. following the war between Sauron and the Elves in Eriador in which both Cirdur's and Amdir's people participated, Celeborn the Wise, Amdir's kinsman in Lindon, persuaded the latter to take up residence in Lothlórien, over which he became king, leaving behind Amroth his son to care for the remnant at Edhellond. Years later, after the War of die Last Alliance took the title of Amroth's father, the Sinda prince departed the haven to assume his father's lordship over Lórien. The Elves of Edhellond gradually dwindled, as more and more departed into the West. The last great wave of departure took place in 1 T.A.-1981, when the wakening of the Balrog in Moria drove many of the folk of Lórien southwards. Amroth himself was among their number, seeking to escape Middle-earth with bis beloved Nimrodel. When Amroth came to Edhellond, he went first to Galadriel and Celeborn, who were then dwelling in Tirith Aear, the Sea-ward Tower which he himself had built so many centuries past. Amroth bade his trusted allies to take up the lordship of Lórien in his stead, as they were the greatest of the Eldar now remaining in Middle-earth. With the departure of its last ship, Edhellond lay empty and forsaken, but in the following year, with the union of Imrazôr the Númenórean and Mithrellas, the Elven handmaiden of Nimrodel, Lond Duilin at least was occupied and maintained by the prince's men. The ancient grove of Eryn laegol itself was left untouched by the Dúnedain and it retained its Elven beauty even into the Fourth Age.
- merp.com wiki